The effects of weight-average molecular （Mw）, molecular weight distribution （MWD）, and isotacticity on the linear viscoelastic behavior of polybutene-1 melts are studied. It is observed that the linear viscoelasti...The effects of weight-average molecular （Mw）, molecular weight distribution （MWD）, and isotacticity on the linear viscoelastic behavior of polybutene-1 melts are studied. It is observed that the linear viscoelastic region becomes slightly narrower with increasing frequency. In frequency sweeps, the transition of the polymer melts flow from Newtonian flow to power-law flow can be observed. The melts with higher Mw and：or broader MWD, as well as higher isotacficity exhibit higher complex viscosity, zero shear viscosity, viscoelasticity moduli, relaxation modulus, broader transition zone, while lower critical shear rate, non-Newtonian index, and the frequency at which elasticity begins to play an important role. The relationship of zero shear viscosity on Mw has been established, which agrees with the classical power law. Furthermore, it is found that the cross-over frequency decreases with increasing Mw and the cross-over modulus increases with narrowing MWD.展开更多
基金financially supported by the National Basic Research Program of China(No.2015CB654700(2015CB654706))Special Foundation of Taishan Mountain Scholar Constructive Program+5 种基金National Key Technology R&D Program of China(No.2011BAE26B05)Shandong Provincial Natural Science Fund for Distinguished Young Scholars(No.JQ201213)the National Natural Science Foundation of China(No.21174074)the Nature Science Foundation of Shandong Province(No.ZR2013BM004)Shandong province science and technology development plan(2012GGA05042)support from the Yellow River Delta Scholar program(Office of National University Science&Technology Park Administrative Committee(China University of Petroleum)
文摘The effects of weight-average molecular （Mw）, molecular weight distribution （MWD）, and isotacticity on the linear viscoelastic behavior of polybutene-1 melts are studied. It is observed that the linear viscoelastic region becomes slightly narrower with increasing frequency. In frequency sweeps, the transition of the polymer melts flow from Newtonian flow to power-law flow can be observed. The melts with higher Mw and：or broader MWD, as well as higher isotacficity exhibit higher complex viscosity, zero shear viscosity, viscoelasticity moduli, relaxation modulus, broader transition zone, while lower critical shear rate, non-Newtonian index, and the frequency at which elasticity begins to play an important role. The relationship of zero shear viscosity on Mw has been established, which agrees with the classical power law. Furthermore, it is found that the cross-over frequency decreases with increasing Mw and the cross-over modulus increases with narrowing MWD.
